Research On The Conjugate Heat Transfer Characteristics And Multi-parameter Influence Mechanism Of Gas Turbine Cooling

Gas turbine is a clean and efficiency power equipment. As the continuous improvement of the thermal efficiency, the turbine inlet temperature is increasingly higher in past decades. Advanced turbine cooling technology become the key factor of turbine design. Modern and advanced turbine cooling structure become more complex and diversified. Overall cooling effectiveness is the result of various cooling components and different heat transfer methods together. With the deep exploration of the turbine cooling technology, the studies of the conjugate heat transfer characteristics which reflects integrated cooling system performance become very meaningful.Firstly, by completing the flow and heat transfer measurements based on the endwall cooling heat transfer mechanism rig, the research built a comprehensive and detailed database including the data of flow parameters, adiabatic parameters and conjugate parameters. The results shown that obvious enhancement could be found in both film cooling effectiveness and overall cooling effectiveness by increasing coolant MFR. Comparing with film cooling effectiveness, overall cooling effectiveness distribution is more uniform, which is due to the influence of internal cooling and solid conduction. Moreover, film cooling affects overall effectiveness near the holes locally.For analyzing the multi-parameters influence mechanism of overall cooling effectiveness, the research established a one-dimensional conjugate heat transfer analysis model which can separate different partial cooling parameters. The model shown heat transfer ratio, film cooling effectiveness and the Biot number of TBC have positive correlation to overall cooling effectiveness, while heat pick-up coefficient and the Biot number of metal are parameters negative with overall cooling effectiveness. The presence of TBC would decrease the sensitivity of both internal and external cooling parameters. More detailed influence characteristics can be found in the contour maps of overall cooling effectiveness. By comparing the experimental results of high and low temperature conditions, it could be found that high temperature in main flow would lower overall cooling effectiveness. The developed temperature prediction method can correct the error from temperature influence. Due to the comprehensive influence of radiation heat transfer in high temperature and humidity conditions, it should be considered in the turbine cooling design that the effects of multi-composition gas in convection/ conduction/ radiation coupled heat transfer.The research was based on the measurements of different flow and heat transfer parameters in different conditions. The related numerical methods and the theoretical model were developed and the influence of different partial cooling parameters, different temperature conditions and radiation was analyzed. The research revealed the conjugate heat transfer mechanism of turbine cooling.